Inaccessible Base -error

[swethapradeep]

Hi ,

I am getting this error

class Baseimage
{
protected:
enum ChannelType
{
  RGB,
  Grayscale
};

unsigned int plane;
unsigned int interbitjump;
unsigned int interbytejump;
public:
Baseimage();
Baseimage(unsigned int plane  ,unsigned int interbitjump ,unsigned int interbytejump):plane(plane),
                                                                                      interbitjump(interbitjump),
                                                                                      interbytejump(interbytejump){ }
virtual void getrasterdata(ifstream&)=0;
virtual void putrasterdata(ifstream&)=0;
};

class RGBclass:protected Baseimage
{
  public:

    unsigned char* red;
    unsigned char* green;
    unsigned char* blue;
}

Baseimage *pbase;
  RGBclass rgb;
  pbase = &rgb;
  cout<<" The channel is"<<pbase->ChannelType<<"\n";

i get an error "Baseimage’ is an inaccessible base of ‘RGBclass’

why do i get that?
-swetha

[Lakshmipathi]

Just a guess,try changing protected to public,

class RGBclassrotected Baseimage

Swetha,Have you tried Debugging tools like GDB or Nemiver? which will help you to detect bugs more easily.

[swethapradeep]

HI,
Thankyou for the reply .I want to access the protected variable in the derived class.So ,i think i should use protected access.
-swetha

[Lakshmipathi]

I haven't done anything related to C++ in last 4 years.Trying to recollect the stuff
Can you post the complete code ..it might help some one from forum to help you .

I'm not sure whether following stmt is correct ---

protected can be accessed by it's public member function or friend function of the class

[Rubberman]

Hi ,

I am getting this error

class Baseimage
{
protected:
enum ChannelType
{
  RGB,
  Grayscale
};

unsigned int plane;
unsigned int interbitjump;
unsigned int interbytejump;
public:
Baseimage();
Baseimage(unsigned int plane  ,unsigned int interbitjump ,unsigned int interbytejump):plane(plane),
                                                                                      interbitjump(interbitjump),
                                                                                      interbytejump(interbytejump){ }
virtual void getrasterdata(ifstream&)=0;
virtual void putrasterdata(ifstream&)=0;
};

class RGBclass:protected Baseimage
{
  public:

    unsigned char* red;
    unsigned char* green;
    unsigned char* blue;
}

Baseimage *pbase;
  RGBclass rgb;
  pbase = &rgb;
  cout<<" The channel is"<<pbase->ChannelType<<"\n";

i get an error "Baseimage’ is an inaccessible base of ‘RGBclass’

why do i get that?
-swetha

Because it is a protected base class. That means only friends can access member variables, even public ones, in that class directly. You might want to reconsider the reasons why you made Baseimage a protected base class. Generally, this is not necessary. If it is a public base class then a first-generation dervied class like RGBclass will be able to acces its variables.

[Rubberman]

Because it is a protected base class. That means only friends can access member variables, even public ones, in that class directly. You might want to reconsider the reasons why you made Baseimage a protected base class. Generally, this is not necessary. If it is a public base class then a first-generation dervied class like RGBclass will be able to acces its variables.

Sorry, this is not exactly correct. A first-generation derived class such as RGBclass can access a protected base class' non-private members, but an external function or other class cannot. Also, the variables you tried to access are protected in the Baseimage class, so only friends of that class, or first-generation derived classes, will be able to access them in any case.